In a jacquard weaving loom, warp yarns are passed through the eye of a heddle. The jacquard device is designed to move these heddles up and down in order to position the warp yarns with respect to one or more levels at which a well thread is in each case introduced during successive operating cycles.
To this end, a known jacquard device comprises a series of hooks which can be selected to optionally move concomitantly with knives moving up and down in counterphase. The hooks are connected to a tackle system which comprises tackle cords which are connected to the heddles by means of one or more harness cords. At the bottom, the heddles are connected to a spring frame or spring box using retracting springs, so that a downwardly directed spring force is exerted on the heddles, and thus via the harness cords and the tackle cords also on the hooks. When a hook is caught by a reciprocating knife, this downward spring force ensures good contact and reliable hooking onto the moving knife by the hook. The abovementioned components form part of the device with which the warp yarns are positioned on the weaving loom during weaving and are referred to in the present patent application as ‘elements (of a device) for positioning warp yarns on a weaving loom’, or ‘positioning elements’ for short.
Each heddle is connected to a harness cord. This connection is achieved by providing a securing element to the end of the heddle. Said securing element, such as e.g. an eye, a resilient fold-back or a clamping element, allows the harness cord to be clamped in the securing element or the harness cord to be turned around the securing element and the returning end part of the harness cord to be connected to the part of the harness cord running towards the securing element, thus forming an eye in the harness cord.
These connections are usually made during the levelling of the eyes of the heddles. During levelling, the connection between each heddle and the harness cord is positioned in such a way that the heddle eye is in a well-defined position with respect to the one or more introduction levels for the weft threads. In order to be able to position the warp yarns extending through the heddle eyes at the correct height in the successive operating cycles, so that successful shed formation across the entire woven fabric is made possible, the heddle eyes obviously also have to be connected to the harness cords at a correct height. In this case, usually all the heddle eyes are connected to their respective harness cords at the same well-defined height.
A harness of a weaving loom sometimes contains thousands of harness cords. The replacement of a harness, for example due to wear of the harness cords or in order to change the configuration of the harness, is a labour-intensive task which involves significant labour costs and which, in addition, also requires long down time of the weaving looms resulting in a corresponding loss in productivity. It is therefore desirable to facilitate these operations by providing constructionally simple connecting means which are easy to handle and make it possible to quickly produce a correct and reliable connection of positioning elements for the warp yarns of a weaving loom.
A number of different types of connecting means have already been developed to provide a quick connection of elements of a jacquard device. EP 0788 562 discloses a connecting device for connecting a harness cord to a tackle cord. This device comprises a first connecting means with an elongate insertion part which ends in a radially widening head, and a second connecting means which comprises a pair of cooperating resilient clamping fingers which are designed to be pushed apart by the head of the first connecting means and to spring back once the head has moved past the clamping fingers. This head is detained in the axial direction by the sprung-back fingers, so that the connecting means are coupled. In order to uncouple the connecting means, the clamping fingers first have to be pushed apart by means of a displaceable part, so that the head is no longer clamped in between the clamping fingers and can be pulled out of the second connecting means.
A drawback of these connecting means is the fact that good coupling of these connecting means depends on two elastically deformable projecting clamping fingers. Such elements are more susceptible to damage, and also have a greater impact on adjacent coupling elements or cords.